1. Field of the Invention
The present invention generally relates to a supplemental cooling system for use with a primary cooling arrangement for electronic equipment during peak demand periods, and more particularly, to a such supplemental cooling system for improving avionics reliability which provides both weight savings as well as accurate control of the cooling air temperature by introducing controlled amounts of liquid CO.sub.2 into a forced air cooling manifold.
2. Background
Reliance on electronic circuitry, i.e., integrated circuits, in aerospace vehicles, such as combat aircraft, has increased dramatically due to the performance improvements and weight savings advantages provided by such technology. Although operationally quite efficient, one disadvantage associated with the use of such electronic circuitry, particularly in connection with avionic equipment, is the technology's dependence on appropriate cooling arrangements for assuring reliable performance of the electronic circuitry.
Examples of known cooling arrangements include forced air cooling, conductive cooling (heat sinks) as well as liquid cooling. Because such cooling systems add weight to the vehicle, they offset the weight savings provided by the use of integrated circuits. Further, these types of cooling systems require constant maintenance, due to the fact that without proper cooling, the degradation in performance of the electronics can be so severe as to threaten the operability of the aircraft, particularly when the electronics are employed as avionics. Moreover, the need for a reliable cooling system increases the overall cost of production of the vehicle.
In addition, the demand on the cooling system to provide an adequate level of cooling varies in dependence on the operational circumstances of the aircraft. For example, there is typically a high demand for cooling of the electronic equipment during the time that the aircraft is on the ground whereas during flight, where temperatures are reduced due to altitude, the cooling requirements of the system are correspondingly reduced.
In order to satisfy such peak demand requirements, cooling systems are typically employed that have a much great cooling capacity than is needed for vast majority of the operational time of the aircraft. As a result, weight, cost and performance requirements of the cooling system are exasperated.